gear ratios
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New User
Joined: Jul 2000
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gear ratios
i have a 77 460 in a 2wd pickup and the thing only gets 7mpg. It runs between 25-2600rpm at 100km (60mph), on 15inh tires. how much of an improvement can i expect from taller gears and how will this change affect my acceleration. Any recommendations would be helpful.
Lead Driver
Joined: Feb 2000
Posts: 5,374
Likes: 46
From: Palm Bay, Florida
gear ratios
Is your engine all stock?? BIG question!!
I had a '78 F150 S/C with a completely stock 460, with Motorcraft 4v carb, C6 automatic, and 3.50.1 rear gears (2wd) this truck got 14-15 mpg all day every day, on regular leaded gasoline, with the a/c on unless I put my foot in those BIG secondaries, I was running a stock size tire L78X15, which is the same as todays 23575R15, I once switched to a 3.00.1 gear and mileage dropped to 11-12 mpg, I never checked rpms but I know when I switched gear ratios that I took the engine out of its optimum running rpm, thus the DROP in fuel mileage.
Hope some of this helps.
I had a '78 F150 S/C with a completely stock 460, with Motorcraft 4v carb, C6 automatic, and 3.50.1 rear gears (2wd) this truck got 14-15 mpg all day every day, on regular leaded gasoline, with the a/c on unless I put my foot in those BIG secondaries, I was running a stock size tire L78X15, which is the same as todays 23575R15, I once switched to a 3.00.1 gear and mileage dropped to 11-12 mpg, I never checked rpms but I know when I switched gear ratios that I took the engine out of its optimum running rpm, thus the DROP in fuel mileage.
Hope some of this helps.
